US Patent 7171969 Brush and method of making brush

The invention relates to a brush that may include a core curved along at least a portion of its length so that an axis of the core defines a curve in a plane of curvature. A plurality of bristles are connected to the core. The bristles may define a cross-section of the brush that varies over at least a portion of the length of the core in a manner that is not geometrically similar. The cross-section of the brush at at least one position along the length of the core may be substantially asymmetric in relation to a plane perpendicular to the plane of curvature. The core may pass through the center of the cross-section of the brush at at least one location along the length of the core.